NEW YORK (CNN) --Children accused more than 4,000 priests of sexual abuse between 1950 and 2002, according to a draft survey for the U.S. Conference of Catholic Bishops.

The survey, to be released February 27, found that children made more than 11,000 allegations of sexual abuse by priests. The 4,450 accused priests represent about 4 percent of the 110,000 priests who served during the 52 years covered by the study.

The report is based on a nationwide survey of church records, and was compiled by the John Jay College of Criminal Justice for the conference. The bishops' conference commissioned the survey to get a better understanding of the scope of the crisis.

CNN reviewed a draft copy of the survey. Officials said it may be slightly changed before its release.

More than half of the accused priests had only one allegation against them. Nearly 25 percent, or 1,112 priests, had two or three allegations, and almost 13 percent, or 578 priests, had four to nine allegations, according to the draft report. Nearly 3 percent, or 133 of the priests, had 10 or more allegations.

The report said that 6,700 of the 11,000 allegations were investigated and substantiated, and another 1,000 were unsubstantiated. The remaining 3,300 were not investigated because the priests involved had died by the time the allegation was made.

The director of the Survivors Network of Those Abused by Priests said Monday that the survey's numbers are low.

"Bishops have tried to hide this for years, so there is no reason to believe all of a sudden they would change their ways," David Clohessy said. "The only prudent thing to do is to assume this is not the entire truth. This is a survey, not a report or investigation."

SNAP, founded in 1989, describes itself on its Web site as the nation's largest, oldest and most active support group for people victimized by religious authority figures.

The president of the U.S. Conference of Catholic Bishops issued a written statement calling the reports "a very sobering and important milestone."

"I have not seen the reports, and so I cannot comment on their substance," the statement from Bishop Wilton D. Gregory said. "But I want to reaffirm that the bishops requested these studies so that we could understand as fully as possible what caused this terrible occurrence in the life of our community to make sure that it never happens again.

"My heart goes out to all who have suffered, and I assure them especially that the bishops are committed to fully implementing the Dallas Charter and will continue to work with the Office of Child and Youth Protection and the National Review Board to reach out to victims and prevent such abuse from occurring in the future," Gregory said in a statement.

The Dallas Charter is a plan developed by the conference in 2002 to protect children from sex abuse by priests. The conference created the review board in 2002 and charged it with commissioning the abuse study.

The head of Voice of the Faithful, a Catholic group formed in response to the priest sex abuse scandal, says some important information is missing from the draft report.

"Although it counts the number of children who have been abused, the number of priests who have abused children, the total financial cost to the church, it does not chronicle the number of bishops who knowingly re-assigned priests who had abused children," said Steve Krueger.

"Without that kind of investigation, there can be no accountability," Krueger said.

The editor of the National Catholic Reporter agreed the church scandal is not just about sex.

"This has long ceased to be just a scandal about sex abuse. It's a scandal about abuse of power and trust, and a breech of faith with people," said Tom Roberts.

Bill Burleigh, a member of the conference's National Review Board, said he would not comment until the survey is released. No clergy serve on the review board.

According to the survey, 78 percent of those abused were between 11 and 17, 16 percent were 8 to 10, and nearly 6 percent were 7 or younger.

The survey also said that several factors contributed to the problem, including failure to grasp its gravity, overemphasis on the avoidance of scandal, use of unqualified treatment centers, misguided willingness to forgive and insufficient accountability.

More than 44,000 priests serve in the United States, according to the U.S. Conference of Catholic Bishops.